Rising cases of coronavirus, as well as influenza and RSV, are putting more strain on hospitals across Canada.

At a news conference Thursday morning, the country’s chief medical officer of health issued a warning about a “dynamic” and tough winter ahead.

Dr. Theresa Tam said COVID-19 cases have already peaked this fall and there has also been growth in Omicron variants. Cases of influenza and RSV are also above seasonal levels.

She points to the return of more in-person activities and falling immunity due to a low uptake in COVID-19 booster shots.

Dr. Tam said the three viruses – COVID-19, influenza and RSV – are synchronized, putting strain on Canada’s hospital systems.

Public health is urging people to take precautions by getting vaccinated against both COVID-19 and the flu, staying home if unwell, practicing good hand hygiene, and wearing face masks indoors and in poorly ventilated areas.

"Although no individual layer of protection is perfect, when used consistently and together, vaccine plus [other] layers can provide excellent protection against COVID-19 as well as other infectious diseases we may encounter," Tam said.

MORE: Wear face masks indoors, federal health officials urge Canadians

“The future is not predetermined,” said Dr. Howard Njoo, the deputy chief medical officer of health. “In many ways we’re in control of our own destinies. So how serious [is] the upcoming season? If people keep up to date with COVID-19 vaccinations, get their flu shot and use all of the protection measures… then I think we might have a less serious season … if people let go and don’t take it seriously. It’s not that it’s necessarily going to be as bad… I think we can control that. It’s up to everybody to do their part.”

The Public Health Agency of Canada said it’s up to each province and territory to implement any masking mandates, but strongly recommends people wear them.

Premier Doug Ford said he encourages Ontario residents to wear a mask whenever they’re in a situation that is less safe, but stopped short of committing to renewed mask mandates in the province.

Zahid Butt, an infectious disease epidemiologist at the University of Waterloo, disagrees.

He said the province should make masks mandatory.

“We shouldn’t wait for more cases, but implement mask mandates now,” he explained. “I don’t think people are wearing them as much as they should. So the only way that the province now can control the surge of cases in the hospitals is not asking, but actually mandating, people to wear masks.”

Butt said indoor settings, like schools, transit and malls should be top priority.

“If that’s not possible, then do a blanket masking everywhere, because this is one of the less intrusive measures to basically reduce transmission of the virus.”

The Waterloo Region District School Board and the Waterloo Catholic District School Board said they follow the advice from the Ministry of Education and public health, but added they are prepared “should masks be reintroduced in schools.”

Region of Waterloo Public Health said it does not have the authority to implement a mandate, but it does "recommend that residents add additional layers of protection when COVID-19, influenza and other viruses are at high or increasing levels, as they are now."

While the region has not implemented new masking rules, the University of Waterloo recently announced that masks will be required for indoor academic activities.

Dr. Nicola Mercer, the medical officer of health for Wellington-Dufferin-Guelph Public Health, said in a statement: "Let me be absolutely clear: don’t wait for a mask mandate to wear a mask. Please wear a mask beginning today in indoor settings."

Dr. Tam admits there is a fatigue factor when it comes to COVID-19 precautions, but said if people understand the surge in cases they may reconsider using masks.